USB: gadget: validate interface OS descriptor requests

commit 75e5b4849b81e19e9efe1654b30d7f3151c33c2c upstream.

Stall the control endpoint in case provided index exceeds array size of
MAX_CONFIG_INTERFACES or when the retrieved function pointer is null.

Signed-off-by: Szymon Heidrich <szymon.heidrich@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index a7c44a3cb2d251b675768907b5c4c95beeb646f7..3b8a8e2d348484cea8461fd5a90cf2720cf9aa1d 100644 (file)
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -1932,6 +1932,9 @@ composite_setup(struct usb_gadget *gadget, const struct usb_ctrlrequest *ctrl)
                                if (w_index != 0x5 || (w_value >> 8))
                                        break;
                                interface = w_value & 0xFF;
+                               if (interface >= MAX_CONFIG_INTERFACES ||
+                                   !os_desc_cfg->interface[interface])
+                                       break;
                                buf[6] = w_index;
                                if (w_length == 0x0A) {
                                        count = count_ext_prop(os_desc_cfg,